Genetic vaccination with naked plasmid DNA provides a long standing cellular and humoral immune response and promotes a shift in the pattern of cytokines produced by the T-cells. Peptides derived from T-cell epitopes can downregulate cytokine production and prevent specific antibody formation and administration of a single dominant epitope may tolerize the response to all the T-cell determinants within that protein.
About 15% of the world population exhibit a hypersensitivity response to common aeroallergens resulting in asthma, eczema, and rhinitis. The most frequently implicated allergens are derived from the house dust mite (HDM) including Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f). From the serological analysis of IgE antibodies from HDM-allergic individuals, a major component (>90%) had a humoral response that was reactive with the group 1 and group 2 allergen. Therefore, using truncated recombinant proteins and overlapping peptides based on the nucleotide sequences, it is possible to generate T-cell epitope maps for human responses to HDM-derived allergens and to allow the development of immunotherapy. However, vaccines using peptides has a substantial limitation that in the peptides are poor immunogens. Recently, studies have shown it has revealed that genetic vaccinations with naked DNA provide long-lasting cellular and humoral immune responses. Long-term persistence of plasmid DNA and foreign gene expression in muscle suggested that muscle is an attractive target tissue for gene vaccination. Many studies have revealed that gene immunization with plasmid DNA encoding whole allergens or protein antigens induced strong T helper type (Th1) immune responses in mice and rats.